1. Field of the Invention
The invention relates to novel phenylethanolamine derivatives and the acid addition salts thereof and more particularly, it relates to novel phenylethanolamine derivatives and the acid addition salts thereof which exhibit .alpha.- and .beta.-adrenergic blocking actions and are useful as antihypertensive agents with less side effects. The invention further relates to a process of producing these compounds.
2. Description of the Prior Art
British Pat. No. 1,321,701 discloses a series of compounds represented by the following formula ##STR2## wherein R.sub.1 is RS, RSO or RSO.sub.2 (wherein R is an alkyl group of 1-10 carbon atoms); R.sub.2 and R.sub.3 each is a hydrogen atom, an alkoxy group of 1-4 carbon atoms, or an alkylthio group of 1-4 carbon atoms; R.sub.4 is a hydrogen atom or an alkyl group of 1-4 carbon atoms; and R.sub.5 and R.sub.6 each is an alkyl group of 1-16 carbon atoms substituted by a phenyl group or a substituted phenyl group, and it is described in the patent specification that these compounds exhibit .beta.-adrenergic blocking action, peripheral vasodilating effect, antiarrhythmic effect and hypotensive effect.
U.S. Pat. No. 3,860,647 discloses a series of compounds represented by the following formula ##STR3## wherein R is hydrogen atom or an alkyl group of 1-4 carbon atoms; R' is an alkyl group of 1-6 carbon atoms, a cycloalkyl group of 3-6 carbon atoms, XC.sub.6 H.sub.4 (CH.sub.2).sub.2 CH(CH.sub.3), XC.sub.6 H.sub.4 (CH.sub.2).sub.2 C(CH.sub.3).sub.2, XC.sub.6 H.sub.4 CH.sub.2 CH(CH.sub.3), or XC.sub.6 H.sub.4 CH.sub.2 C(CH.sub.3).sub.2 (wherein X is hydrogen atom, a hydroxy group, or a methoxy group); and Y is a hydrogen atom or a hydroxyl group, and it is described therein that these compound exhibit .beta.-adrenergic blocking action.
Also, British Pat. No. 1,266,058 discloses a series of compounds represented by the following formula ##STR4## wherein R' is an aralkyl or aryloxyalkyl group optionally substituted by one or more OH or O-alkyl groups in the aryl residue, and it is described therein that these compounds exhibit .alpha.- and .beta.-adrenergic blocking actions and are useful as drugs for treatment of hypertension and angina pectoris.
In the field of treatment of hypertension, the employment of peripheral vasodilators for hypotensive purposes encounters a serious disadvantage in that there occurs a reflex tachcardia induced by the decrease of the blood pressure. Recently, an effort for overcoming this difficulty has been made by using peripheral vasodilators together with .beta.-adrenergic blocking agents possessing an action for controlling reflex tachcardia but this treatment system is objectionable in that two different kinds of medicaments are required and they must be administrated separately.